Athletes take pictures during a biathlon training session ahead of the Sochi 2014 Winter Olympics in Russia. The make of phone isn't clear. Photograph: Alexander Hassenstein/Getty Images

Swiss athletes at the Sochi Olympics who received gifts of Samsung Galaxy Note smartphones have reportedly been told to cover up Apple logos on iPhones if they use them at the opening ceremony - but both Samsung and the International Olympic Committee deny having told them to.

A report in Bluewin, a Swiss website, said that Swiss athletes received beer tankards, toiletries, and Galaxy Note 3 smartphones - but added that “the gifts came with linked demands”. As an Olympic sponsor, it said, Samsung had said that there should be no rivals’ brands in TV pictures - and so those who attended the Opening Ceremony should cover logos on iPhones.

Olympic sponsors are notoriously sensitive about rival brands gaining exposure at their expense. The 2012 Olympics saw “branding police” responsible for ensuring that sponsors’ brands were protected, as well as policing inside event locations to prevent “guerilla advertising” by non-sponsor brands.

But asked by the Guardian about the claims of an enforced coverup, a Samsung spokesperson said: “Samsung did not request any action of this nature from athletes attending the 2014 Sochi Winter Olympics. All commercial marketing around the games is overseen by the International Olympic Committee (IOC) and Samsung has not been involved in any decisions relating to branding of products used by athletes at the games.” Samsung suggested asking the IOC.

When asked by the Guardian whether it had instigated the move, the IOC’s press office said: “it is not true. Athletes can use any device they wish during the Opening Ceremony. The normal rules apply just as per previous games. The Samsung Note 3 that were distributed are a gift to the athletes, so they can capture and share their experiences at the games, and the phones also contain important competition and logistical information for competing athletes.“

The IOC named the Galaxy Note 3 the “official Olympic phone” on Tuesday and said it would provide one to all of the athletes “to enjoy, capture and share” their experience at the games - although athletes are also told that any video or audio that they collect of events, competitions or “other activities which occur at Olympic venues (including the Olympic villages)“ must not be “uploaded and/or shared to a posting, blog or tweet on any social media platforms, or to a website”.

Samsung and Apple are fierce competitors in the smartphone and tablet sectors, and have clashed repeatedly in the courts - with Apple winning a huge damages case in California after alleging that Samsung copied elements of its earlier iPhone designs. Samsung, in response, has produced adverts mocking people queueing for new phones outside Apple-style stores, while also pouring billions of dollars into advertising and marketing efforts - including its sponsorship of the Olympics.